Computer



W; M. RADER Jan. 7, 1947.

COMPUTER Fil ed Dec. 16, 1944 v 2 Sheets-Sheet l frzvwzipr' 77 M flw L AZZorneys 1 Jan. 7, 1947. v w, RADER 2,413,888

COMPUTER Filed Dec. 16, 1944 2 Sheets-Sheet 2 .Zr'zveniar /M v%%m I Patented Jan. 7, 1947 atlases UNITED STATES PATENT OFFICE COMPUTER.

William M. Rader, Hoven, S. D.

Application December 16, 1944, Serial No. 568,523

2 Claims.

This invention relates to computing devices.

It is a general'object of the invention to provide means for quickly and accurately computing results from a table or tables of figures to eliminate time consuming and frequently inaccurate computation with pencil and paper.

More particularly it is an object of the invention to provide a mechanical computer of simple construction wherein the device can be operated to shift a movable factor table relative to one or more stationary factor tables in accordance with the computation desired and wherein such movement will accurately and quickly disclose the desired result.

These and other objects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same parts throughout the views, and in which:

Figure 1 is a plan View of an embodiment of the invention;

Figure 2 is an end elevation thereof; and

Figure 3 is an enlarged fragmentary sectional view of one of the stationary factor elements and the movable web.

The apparatus includes a baseboard 4 having one edge thereof secured to an upright back 5 with the baseboard preferably slanting as shown in Figure 2. Mounted across the lower end of the baseboard 4 is a reel 6 rotatably supported by brackets l suitably secured to the baseboard 4 and supporting the ends of the reel shaft 8. As shown in Figure 1, spring washers 9 are interposed between the ends of the reel 6 and the reel supporting brackets l to provide a slight frictional drag on the reels 6 so that they will not move about the axes accidentally but can be turned freely by rotating the crank handles 10 secured on the ends of the reel shaft 8.

Extending across an upper intermediate portion of the baseboard 4 is a reel I! supported by brackets [2 which are adapted to receive the reel shaft IS, the latter having cranks M on its ends. Spring washers l5 similar to the washers 9 on the reel unit first described are also provided to produce a slight frictional drag on the reel H.

Located above the intermediately disposed reel H is a third reel l6 having a shaft ll supported by brackets l8. A web l9 has one end thereof wound about the lower reel 6 and has its other end wound about the intermediate reel ll, the web being extended about the idler reel H5 at the upper side of the baseboard 4. As a result that portion of the web 19 between reels 5 and l I gives the operator a view of one side of the web l9 and that portion of the Web extending between and lying over the reel H and the idler reel it giving the operator a view of the opposite side of the web from that side exposed between reels 6 and l I.

On the right hand end of the reel shaft 3 is a sprocket 20 and a second sprocket 2! is mounted on a stub shaft 22 extending out of the right band edge of the baseboard A chain 23 ex-- tends between the sprockets 2B and El and the chain carries an outwardly projecting pin 2 which is adapted to engage a stop element 25 extending from the edge of the baseboard adjacent the sprocket 2|. As a result the reel 6 can be rotated a number of revolutions in either direction between the limits of movement of the pin 26 on the chain 23 on one side of the stop 25 to the other.

Between the reels 6 and H is a bar 25 having downward extensions 21 across its ends so that the major portion of the underside of said bar 26 i elevated slightly from the upper surface of the baseboard 4. Across each end of the bar 6 is a retainer 28 having one end secured to the baseboard as by a screw 29 and having its other end adjustably connected to the baseboard by a nutted bolt 30. By means of this structure the bar 26 can be shifted slightly up or down the slant of the baseboard 4 and can be clamped in the desired adjusted position. This is done to permit the ready assembling of the apparatus and the exactly proper setting of the bar 25 relative to the lines on the web I9. The webs are not always precisely uniform and they are subject to some small changes in linear dimensions. When the latter occurs the apparatus can be quickly and easily corrected.

A flat plate 31 is secured to the top edge of the upright back element 5 and said plate 3! extends over the idler reel is and is provided with a free edge 32 lying across and closely adjacent the web I9.

Referring to Figure 1 the bar 26 is provided with indicia extending thereacross and it is shown bearing numbers 1-1, 1-15, 2-1,

p 2-15, etc., to 12-15 at the right hand end of 26 and above the numerals 1-15 on said bar 26. The sets of numerals on the stationary bar 26 represent day-s of the month such as January 1, January 15, and February 1 in the first three sets of numerals reading from the left. The sets of numerals on the face of the web l9 which were quoted above also represent dates, those three sets in the vertical row at the left being March 31, April 1 and April 2. The stationary plate 3| which extends from the vertical back element 5 is provided with numbered spaces therealong and across the width of the web IS the numerals being in units from 1 to 10, in tens from to 100 and in hundreds from 100 to 1000. In the illustrated example these numbers repsent the amounts of principal upon which inter,- est rates are to be reckoned. That portion of the web l9 which extends between the upper portions of the reels I I and l 6 is a portion of the op.- posite side of the web from that side bearing the dates adjacent the stationary bar 25. This second side 'of the web l9 bears longitudinally arranged rows of figures representing amounts of interest.

The figures on the drawings are arranged for computation of interest on different amounts ofmoney at a rate of six per cent (6%). For instance, the apparatus has been set so that the date on the web 19 immediately adjacent the date 1-1 or January 1 on the stationary bar 26 is 3-31 representing March 31. The device would be so set to determine interest for the ninety day period from January 1 to March 31. If the amount borrowed is one hundred dollars ($100) the operator notes the number 100 on the stationary plate 3| at the upper side of the apparatus and the amount of interest is indicated immediately therebelow on the opposite side of the web IS, the amount shown being $1.50. At the right hand end of the bar 26 is the date 12-15 and immediately thereabove on the web I9 is the date 3-14. This indicates another ninety day period and, of course, the amount of interest on the $100 principal would bethe same. Only a comparatively few sets of dates have been shown on the web l9 and relatedsets of interest figures have also been shown to illustratethe invention. Naturally, the rows of dates extending longitudinally of the web 19 would be carried out to provide complete sets of dates for the entire year.

I have shown the dates on the bar 26 as representing the first and middle of each month. Of

course, if the device is made wider months can be subdivided more than shown in the drawings.

It should be noted that each column of dates extending longitudinally of the web is intended to be carried out consecutively for all the dates in the year and that the interest columns are carried out so that it is possible to figure from any date on the stationary bar 26 to any day of the year and the proper amount of interest at the predetermined rate will be indicated on the interest table side of the web l9.

Should it be desired to figure interest from January 5, which does not appear on the bar 26, to any desired date in the year the date in question would be moved to the position occupied by March 31 in the drawings immediately adjacent January 1 on the bar 26, and the operator would then note the principal which might be $100. The interest bearing portion of the web I 9 would be wound toward the operator four spaces beyond the space bearing the interest figure $1.50 in the drawings to give the correct amount of interest from January 5 to the datedesired.

It will, of course, be understood that various,

changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.

What I claim is:

1. In a computer, an. idler reel; a pair of'winding reels having opposite'ends of a web wound thereupon one of said Winding reels being disposed between the other of said. winding reels and said idler reel, said web passing fromone of said winding reels about the idler reel and thence to the other of said Winding reels, whereby portions of opposite sides of said'web are exposed to view, indicia on each side of said web, all of saidreels lying in substantially the same xial plane, and a pair of relatively stationary elements having in dicia thereon, one of said stationary elements being disposed adjacent the exposed portiCILOfQne side of said web, and the other of said stationary elements being positioned adjacent the exposed portion of the other side of said'web.

2. The structure in claim 1, and the axes of said reels being fixed, one of said stationary elements being adjustably shiftable longitudinally of said web, and means for clamping said last mentioned element against accidental displacement.

WILLIAM RADER, 

